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Problem IC91395
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Status: Closed |
THE QUERY COMPILER CAN ASSUME A DEFAULT CARDINALITY FOR A CGTT |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
In environments where real-time statistics is not enabled, if
you
do not perform runstats on a CGTT, the query compiler will use a
default cardinality estimate of 1000. This behaviour differs
from DGTTs, where the query compiler will try to estimate the
table cardinality based on the object's physical size. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All DB2 V10.1 on LUW users. *
****************************************************************
* PROBLEM DESCRIPTION: *
* In environments where real-time statistics is not enabled, *
* if you do not perform runstats on a CGTT, the query compiler *
* will use a default cardinality estimate of 1000. This *
* behaviour differs from DGTTs, where the query compiler will *
* try to estimate the table cardinality based on the object's *
* physical size. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 V10.1 Fix Pack 3 or higher. *
**************************************************************** |
| Local Fix: |
After modifications are performed on the CGTT, for example,
after it is populated with data, perform RUNSTATS on the CGTT |
| available fix packs: |
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
Fixed in DB2 V10.1 Fix Pack 3 |
| Workaround |
After modifications are performed on the CGTT, for example,
after it is populated with data, perform RUNSTATS on the CGTT |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC95311
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 06.04.2013
26.08.2014
26.08.2014 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.3
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 |
| 10.1.0.3
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